Re: [Vala] How to get a const substring without copying?

[Thijs Vermeir <thijsvermeir gmail com>]

On Sun, Nov 6, 2011 at 3:44 PM, PCMan <pcman tw gmail com> wrote:
> Hello,
> It's me again.
> In C language, sometimes we do this:
> char* uri = "ftp://140.112.172.1";;
> char* ip = str + 6;  // get the IP part of the string without copying.
>
> With vala, either string.substring() or string[start:end] needs copying.
> Is it possible to do the above in vala? In trivial cases this causes no
> difference.
> However, for more performance critical code, this can reduce many
> unnecessary malloc/free.
> Is this possible in Vala anyways?
> I cannot find any clues in the tutorials and the docs.

Yes,
this should do it:

public static void main (string[] args)
{
  string hello_world="hello world";
  unowned string world=(string) ((uint8 *)hello_world + 6);
  print ("%s\n", world);
}

Gr,
Thijs

> Thanks
>
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